Tractor



FIG. 1 is a front, left perspective view of a tractor;

FIG. 2 is a rear, left perspective view of the tractor;

FIG. 3 is a left side view of the tractor;

FIG. 4 is a front view of the tractor;

FIG. 5 is a rear view of the tractor; and,

FIG. 6 is a top view of the tractor.

The broken line showing of the windshield wiper, wheels, and lower mechanical portions of the frame, and is included for the purpose of illustrating unclaimed portions of the tractor and forms no part of the claimed design. 

CLAIM The ornamental design for a tractor, as shown and described. 